Concrete insulation blanket



Jan. 7, 1969 w. c. BROCK l 3,420,022

l CONCRETE INSULATION BLANKET Filed Sept. 20. 1966 Frs: .z ,37

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. LZBY y iframe-rs United States Patent O 3,420,022 CONCRETE INSULATION BLANKET Wayne C. Brock, 4409 Curve Ave., Minneapolis, Minn. 55424 Filed Sept. 20, 1966, Ser. No. 580,738 U.S. Cl. 52-302 12 Claims Int. Cl. E04b 1 62; E04c 2/04 ABSTRACT OF THE DISCLOSURE A portable blanket for protecting concrete surfaces having a water impervious elongated plastic film cover 'surrouding one or more sheets of fiexible material as expanded polystyrene sheet members. One Way valves mounted in the ends of the cover allow air to be discharged from within the blanket.

Summary of invention This invention relates to a reusable and portable blanket for protecting freshly poured concrete from low temperatures during the curing period.

It is a common practice in the construction industry to pour concrete slabs, walls or columns during sub-freezing temperatures. To provide the freshly poured concrete with durability and strength, the concrete must be protected from freezing during the first few days after pouring. In addition to preventing the concrete from freezing it is important that the moisture in the concrete be retained in order to have an effective curing of the concrete. To give the concrete body maximum strength the concrete should be cured at approximately 70 F. for three days or 50 F. for six days.

In sub-freezing temperatures, straw, sawdust and other insulating materials and blankets having bat glass fiber insulation, have been used to keep the concrete body sufficiently warm and to prevent premature drying of the concrete. These insulating materials absorb water and they 'are not rapidly removed from the concrete and cannot be effectively and etiiciently reused. It is also a practice to enclose the concrete in a temporary enclosure to maintain the desired temperature for curing during subfreezing weather. This is an expensive procedure and does not overcome the drawback of keeping the moisture in the concrete to provide for proper hardening of the concrete.

Brieiiy described, the insulating blanket of this invention is readily used to cover newly poured concrete and provides an insulating blanket which has effective thermo insulating characteristics so as to retain heat in the body of the newly poured concrete over an extended period of time during sub-freezing weather. The blanket also is a water vapor barrier which prevents loss of moisture from the new concrete.

The thermo insulation blanket of this invention has a seamless water impervious skin or cover surrounding one or more sheets of flexible synthetic plastic insulating material. The skin is highly resistant to deterioration resulting from chemicals in the concrete and will not adhere to the concrete surface. These sheets of plastic material are light in weight, flexible and have a low K factor providing effective thermo insulation. In addition, the plastic material is water repellent and has sufficient rigidity to stay in place within the cover. The plastic material has shape memory characteristics `and it will return to its original fiat shape after it is compressed or deformed. These characteristics permit the blanket to retain its shape and eliminates the disadvantage of sagging common to the known concrete insulating blankets.

To provide for the escape of air and water which may F-ice enter the blanket during field use the opposite ends of the blanket are formed with one-way valves which allow the air and water to be discharged from within the blanket to an outside location when the blanket is rolled up for storage. The valves facilitate the removal of air from within the cover during the positioning of one or more sheets of plastic material within the bag. The use of oneway valves eliminates costly and cumbersome procedures of manufacturing the blanket.

In the drawings FIGURE 1 is a vertical sectional view of a new concrete fioor covered with the insulating blankets of this invention;

FIGURE 2 is a perspective View of an insulating blanket in a fiat unrolled position;

FIGURE 3 is an enlarged foreshortened sectional view taken along the line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged sectional View taken along the line 4 4 of FIGURE 2; and

FIGURE 5 is a fragmentary sectional View of one sheet of the expanded polystyrene or other closed cell flexible plastics insulating core of the blanket.

Referring to the drawings there is shown in FIGURE 1 a newly poured concrete floor 10 supported on beam structure 1'1. In order to provide for proper curing of the concrete in sub-freezing weather, the enclosed portion of the structure is heated, as indicated by heat arrows 12 and the top surface of the concrete floor is covered with a plurality of side-by-side thermo insulating blankets 13 and .14. The entire top surface of the concrete floor is covered with a plurality of blankets with the adjacent edges of the blanket being overlapped to insure that outside air does not contact the freshly poured concrete. Weights, as elongated wooden boards, may be placed on top of the blankets to prevent the wind from uncovering the concrete floor. Blankets 13 and 14 have sufficient heat insulating characteristics to retain the heat in the newly poured concrete for an extended period of time under sub-freezing weather conditions. In addition, the blankets do not absorb moisture and thereby retain the moisture in the concrete to assure proper curing of the concrete. The materials used in fabricating the blankets are Water resistant and will not stain the concrete surface.

As shown in FIGURES 2 and 3, thermo insulating blanket indicated generally at 13 comprises a seamless tubular cover or skin 16 surrounding a core of insulation material 17. The opposite ends 18 and 19 of the cover are sealed and have one-way valves 21 and 22 which allow air, water and similar fluids to flow from the inside of the skin to the atmosphere.

Skin 16 is waterproof, airtight, remains pliable without cracking at extremely low temperatures, and does not adhere to the concrete. These characteristics of the skin enable the blanket to be readily removed from the concrete after the concrete is cured. Preferably, skin 16 is a black polyethylene film having a thickness of six to eight mils.

As shown in FIGURE 3 the, core of insulating Inatel rial 17 comprises three sheets 23, 24 and 26 of foamed plastic material, preferably expanded polystyrene, polyethylene or other 'closed cell flexible plastic. The core may be one or more layers of foamed plastic material depending on the heat insulating characteristics desired. Expanded polystyrene or polyethylene sheets are iiexible, water repellant, lightweight and non-water absorbant. They also have dimensional stability and have the ability to recover to their original shape when depressed. The sheets are flexible so that they can be rolled. When the sheets are unrolled they have a fiat memory. FIGURE 5 shows a sheet 23 of expanded plastic material as being depressed with a force 27 forming a recess or depression 28 in the top surface of the sheet. As soon as force 27 has been removed from the sheet of expanded plastic material the memory force of the material, indicated by dotted arrows 29, returns the sheet of expanded plastic material to its original flat shape. Thus, the blanket will always have substantially the same thickness and uniform insulating characteristics since the insulating material does not mat. The sheets of expanded plastic material 23, 24 and 26 are suiciently rigid to provide the blanket with a dimensional stability. When the blanket is held in an elevated position the insulating material 17 does not sag or change its position in the skin whereby the blanket will retain its at shape and can be repeatedly used in other job sites.

As shown in FIGURE 4, a one-Way valve 22 is sealed in the end 19 of cover 16. Valve 22 can be any suitable construction and is illustrated as a tube 31 having a stepped longitudinal passage 32. A valve disc 33 interposed in passage 32 moves to open and closed positions relative to a shoulder 34 to allow air and water to flow out of the area between the cover 16. A light spring 36 holds valve disc 33 against the shoulder preventing air from flowing into the cover. The inner end of spring 36 is anchored to a transverse pin 37 mounted in the inner end of tube 31. The opposite end of spring 36 is connected to the center portion of valve disc 33. The number and the location of the one-way valves may vary to handle increased volumes of air and water which may be trapped in the cover. The one-way valves provide a drainage opening for water which may seap into the blanket through a rip in the skin. Valve disc 33 and spring 36 may be replaced with a removable stopper (not shown) whereby tube 31 functions as a drain. The core of insulating material being water repellant and non-water absorbant is not affected by water getting into the blanket. Even if the skin is cut or ripped the blanket can be effectively used on another job site.

In the manufacturing of the blanket, seamless polyethylene tubing is used which has a diameter sufficient to snuggly receive the core material 17 in a tlat condition as shown in FIGURE 3. The blanket may be of any practical length preferably limited to a convenient size and weight for manual transportation. For example, the blanket may be three to six feet wide and one to three inches thick and have a length of 20 to 30 feet.

The core of insulation material 17 is inserted longitudinally into the seamless polyethylene tubing or cover 16 with both ends of the cover open to exhaust air from the open ends. The ends 18 and 19 are then sealed with each end having a one-way valve 21 and 22. In some blankets the one-way valve may be located only at one end of the blanket.

The cover 16 and core insulation material 17 are suiciently flexible to allow the blanket to be rolled for handling and storage. During the handling of the blanket and when the blanket is in the rolled position the core insulation material 17 does not sag in the cover 16 so that the core insulation material 17 of the blanket will unroll to a flat position.

This description and drawing is directed to the preferred embodiment of the insulation blanket of this invention. It is intended that various omissions, substitutions, changes in dimensions and details of the cover, insulating material, and valves may be made by those skilled in the art without departing from the invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An insulation blanket for covering concrete comprising a at, exible and water impervious tubular cover, at least one elongated and fiat layer of heat insulating material enclosed by said cover, the opposite ends of said cover being closed to conne the insulating material within the cover, said insulating material being a generally flat, tlexible, lightweight material which can be rolled and returned to its flat shape whereby the insulating material remains in position in the cover, and one way vent means attached to said cover for venting tiuids from within the cover and preventing water from owing into the cover.

2. The insulation blanket of claim 1 wherein the heat insulating material includes a plurality of face-to-face sheets of expanded polystyrene.

3. An insulation blanket comprising a at, flexible and water impervious tubular cover, at least one elongated and flat sheet of heat insulating material enclosed by said cover, the opposite ends of said cover being closed to conne the insulating material within the cover, said insulating material being a diexible, lightweight sheet member which maintains its original at shape and does not absorb water whereby the insulating material does not mat or sag in the cover and means attached to said cover for venting uids from within the cover, said venting means comprising one-way valve means operable to only allow fluid to ow from the space enclosed by the cover.

4. The insulation blanket of claim 3 wherein said cover is a tube of polyethylene film.

5. The insulation blanket of claim 4 wherein the polyethylene iilm is black and has a thickness of about between six to eight mils.

6. The insulation blanket of claim 3 wherein the heat insulating material is a sheet of expanded polystyrene.

7. The insulation blanket of claim 3 wherein said oneway valve means includes one-way valves attached to opposite ends of the cover.

8. The insulation blanket of claim 3 wherein said cover is a tube of polyethylene lm and said one-way valve means includes one-way valves heat sealed between top and bottom sides at the opposite ends of the polyethylene lm.

9. The insulation blanket of claim 3 wherein the heat insulating material includes at least one sheet of closed cell exible plastic material.

10. The insulation blanket of claim 3 wherein the heat insulating material includes a plurality of face-to-faoe sheets of closed cell flexible plastic material.

11. An insulation blanket for covering concrete comprising a flat, flexible and water impervious tubular cover, at least one elongated and at sheet of heat insulating material enclosed by said cover, the opposite ends of said cover being closed to conne the insulating material within the cover, said insulating material being at least one flat, ilexible lightweight expanded polystyrene sheet mernber which maintains its original fiat shape, can be rolled and returned to its at shape and does not absorb water whereby the insulating material does not mat, sag or curl in the cover and one-way vent means attached tosaid cover for venting fluids from within the cover and preventing water from owing into the cover.

12. The insulating blanket of claim 11 wherein the heat insulating material includes a plurality of face-toface sheet members of expanded polystyrene.

References Cited UNITED STATES PATENTS 2,853,399 9/1958 Shoults l6l-43 X 2,927,626 3/1960 Corwin 161-43 2,956,310 10/1960 Roop. 2,971,616 2/1961 Bayley 52-406 3,162,566 12/1964 Katz 16l-45 X 3,192,099 6/1965 Beckman 161-161 X 3,246,443 4/1966 Slemmons 161-43 3,264,165 8/1966 Stickel 52-309 X 3,350,553 11/1967 Cline 161--45 X JOHN E. MURTAGH, Primary Examiner.

U.S. Cl. X.R. 

